1. Field of the Invention
This invention relates to parking apparatus for motor road vehicles, of the kind comprising a pair of ground-engaging parking rollers adapted to be mounted on the vehicle so as to be movable from a retracted position beneath the vehicle to an operative position in which they engage the ground one at each side of the vehicle adjacent to a pair of road wheels of the vehicle and cause the said pair of road wheels to be lifted from the ground. The axes of the parking rollers are so disposed that on rotation of the parking rollers in the operative position the adjacent end of the vehicle moves sideways. Power mechanism is provided for moving the parking rollers from the retracted position to the operative position.
2. Description of the Prior Art
In the case of a rear-wheel drive passenger car, the pair of road wheels in question is normally the unsteered driven rear wheels--see for example my U.S. Pat. Nos. 2,964,118 and 3,202,231. In this case, as described in those U.S. Patents, the rollers when in the operative position are preferably oppositely inclined, one ahead of and one behind the centre line of the pair of wheels, and are arranged so as to engage the sides of the tyres of the rear wheels so as to be driven frictionally from them for executing sideways movements, though it would also be possible to employ the present invention with other forms of auxiliary wheel or parking roller, e.g. one driven through a separate transmission or having its own independent power drive. In the case of a front-wheel drive car or of a goods trailer vehicle, the pair of wheels is normally the undriven rear wheels of the car or trailer respectively--see my U.S. Pat. No. 3,120,398. In this case, when the rollers have been lowered, the vehicle is driven through its normal driven wheels and the end supported by the rollers then follows a sideways course dictated by the axes of the rollers.
In my above-mentioned U.S. Patents it was proposed to mount such parking apparatus on an axle carrying the pair of road wheels, i.e. in the first case referred to on the rear axle of the car. This adds somewhat to the unsprung weight of the axle suspension system. It is also impracticable in the case of a car having independent rear wheel suspension and no rigid rear axle.
In my U.S. Pat. No. 3,401,762 I have described and claimed a parking apparatus of the kind described above, in which at least the greater part of the assemblage comprising the rollers, their mountings and the power mechanism is adapted to be carried on the sprung part of the vehicle, and parts carried upon the mountings of the ground-engaging rollers are arranged to engage unsprung parts of the vehicle adjacent to the said pair of wheels towards the end of the movement of the rollers into the lowered position, so as to impart an upward thrust to the said unsprung parts, whereby the said pair of road wheels is lifted from the ground while the weight of the adjacent end of the vehicle is supported by the ground-engaging rollers through the road springs and the said unsprung parts.
In the embodiments described in U.S. Pat. No. 3,401,762, each ground-engaging rollers is rotatably mounted at one end of an arm, the other end of which is adapted to be pivotally connected to the sprung part of the vehicle, so that the arm is capable of swinging the roller from the retracted position to the lowered position and vice versa.